Flamethrowers 2005.
This is a mini version inspired by this
thread on 4HV started by Psyko.

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The left photo shows an insulin syringe with 27 G needle spraying methylated spirit (= "metho" - ethanol/methanol) through a little propane burner flame. The right
photo shows kerosene which burns more completely but is thicker.

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The left photo shows a 10 ml syringe with 18 G needle and shows the
patch where the unburnt metho lands. The center photo shows an
insulin delivery pen with a 30 G needle which was not particularly
impressive. The second arrangement had the needle fixed in the flame
and was a lot easier to control. The right photo shows
crossed beams (remember Ghost Busters - Never cross the beams).

I used a 27 G scalp vein (butterfly) needle taped onto my little butane
torch. The needle was bent into the flame. On its own this gives too much
flow with a droopy and yellow flame. I got better results with crimping the
end of the needle in pliers. When I overdid this and blocked it I bent it
off to break it and this is what gave the best results. No doubt it is
constricted in the end. The beam is visibly flatter with less tendency to
fall but there is still unburnt metho droplets at the end of the 'beam'.

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The left photo shows a shot onto our garage ceiling. The
ceiling shot was interesting because the flame tries to rise but can't so it
gives a strange diffuse glow rather than flames. It looks rather unnatural
in the photo but was untouched (other than basic
cropping/exposure/compressing). More fun than an English essay
according to my son. The right photo shows my prowess with the
flame thrower. The pressure is relatively low coming from a 20 ml syringe and
long medical extension tubing and held in the other hand that you don't see.

A little more laser like quality but still rather finicky to keep
alight along the whole length. Again, these are the "best of"
pictures.

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This is the desired effect. Now, how can I solubilise some Strontium in the
alcohol to get a red flame like Luke's light sabre?

Vortex
ring launchers 2006First the small one made out of a large can and a rubber glove and
held over a smoke generator. Gives a surprisingly strong puff of wind up to
10 feet of more away. I cut a 50% diameter hole cut in the base. Fill with
smoke, pull the rubber glove membrane back and let go to fire. A smoke
ring shoots out and sails across the room.

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The small can makes an effective and simple vortex generator.

Next the big one made from a discarded compost tumbler measuring 80 cm
diameter and 90 cm deep and mounted on a sturdy frame.

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The left photo shows me finally finding a use for those old bike
tubes. The centre photo shows the elastic straps attached to the
diaphragm made of a rubberized picnic blanket. The right photo shows the
heater for the commercial fog fluid.

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The left photo shows the construction team from left of me, Chris, Michael and
Justin. The centre photo shows a flash outdoors on
a still night which highlights the vortex well. The right photo
shows that there is no escape from the speeding vortex.

Above shows video 9MB of slow and fast shots. Run mouse over
to play.
If that doesn't work try
here.

A later version uses a
commercial fog generator such as used in discos. The fog is a
proprietary mix of propylene glycol and triethylene glycol in water.

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Above shows another slightly smaller vortex
ring launcher made for the Physics Dept. Improvements include being
lighter, portable and having an internal light and sights.
The left photo shows the red internal light. The centre photo shows
a basketball shot. The right
photo shows the rings in a lecture theatre (with smoke detectors turned
off) being lit by a projector. (Perhaps a use for the Windows blue screen of
death).

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These photos show an oscillation that develops in a slow moving ring (the
top one) is passed nearby by a faster ring. The slow moving ring becomes
ellipsoidal in each axis alternately which lasts for several cycles.

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The photos above show some unusual vortex ring shots.
The left photo shows a "UFO" shot which has bee rotated to be
vertical. The centre photo shows a sunset shot of multiple rings. The
right photo shows a ring passing into a tree with the physics
building in the background. The flash fired for this one giving a
strange quality.

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I am now mobile with my vortex generator. My 300W Honda generator is a bit
weak for the 700W smoke generator so has to run through a variac and takes
longer to heat.
Add a lick of paint, wheels and a trailer and I can take it anywhere. Had
vague ideas of the kids having a small business hiring this out for kiddies
birthdays and the like. I still would like to make a huge one to fire
vertically. Or a truck sized one to fire at crowds at events.

Above shows the long range shots taken in a school gym for the Discovery
Channel video. They show the range of the rings and the clarity after a long
run. These are going at walking pace and tend to drift up being slightly
warm from the smoke generator.

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Above shows the commercial fog generator (about AUD $80 at Dick Smith's)
as used in nightclubs. The fog is
a proprietary mix of propylene glycol and triethylene glycol in water and a
$10 1 litre container lasts all day.

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Above, my son, Chris, blows underwater vortex rings of air in the pool.
Dolphins can do this as well.

Colored smoke rings 2008
Colored smoke has been tried before but I gather are prone to leaving a
colored residue (normal smoke generators will leave a liquid residue if
aimed against a surface but it will eventually evaporate).
So here's what I tried instead.

I used a standard boating flare that produces orange smoke. Under Australian
maritime law it is required that you carry 2 red light flares for night and
two smoke flares for day. This pack of 4 is available for AUD$70. Each
smoke flare burns for 60 seconds. If you cut each flare into 1 inch slices
with a hacksaw, then the 10 smoke flare slices will cost $7 each for 12
seconds bright orange smoke.

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The left photo shows the flares with a section cutout. The next photo
shows that it won't work in open air as it just burns without orange smoke. Presumably oxygen must be excluded so
the next photo shows a short aluminum tube as a firing chamber with ignition
by my MAPP gas blowtorch. The right photo shows the dense orange smoke
resulting.

Microwave abuse
(Dec 2005)
I was given a working microwave oven (MO). I have never been game to invade
the wife's kitchen to use/abuse her MO but now I have a chance to
experiment.

First off, here is a CD burner (literally). Place a CD (or presumably DVD)
in the MO and run it. After a second or so sparks appear and shortly after
flames after which it is wise to turn off to avoid magnetron damage in view
of the lack of loading.

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Left and centre photos show the sparks then flames. The right photo
shows "Windows 95 Starts here" and presumably ends here as well.

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This is a 2 second exposure capturing the fine branching sparks as they
spread out over the CD.

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The fractal patterning is shown nicely if the CD backing is translucent or
transparent when held up to the light.

Aerogel 2006
Aerogel is an exotic solid that is ultra light weight
with many remarkable properties.

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Left photo shows a block of aerogel (from eBay, where else?). The
right photo shows a live 0.5 g Monarch butterfly sitting on the aerogel
which weighs 0.8 g. Volume of the aerogel here is just on 10 cc hence it is
80 mg/cc. At about AU$ 80 for 0.8 g, this makes it about 4 times as
expensive as gold per unit weight.

Aerogel is typically 99.8% air and is is made by high temperature and
pressure-critical-point drying of a gel composed of colloidal silica
structural units filled with solvents. The resulting silica dioxide
structure is sponge like with microporosity on a nanometer scale. It has
many unusual properties including extreme lightness (as low as 3 mg/cc),
excellent insulating properties (39 times better than fibreglass) and high
electrical insulation (1018 ohm cm compared with glass 1015).
It was discovered in the 1930's but came into the public eye with
aerospace uses
including Mars Rover insulation and as a comet dust collector with Stardust
2.

It can support 4000 times its own weight.

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It shows laser beams clearly just like thick smoke. This photo does
not really show how clear it actually is.

The sparkling
electrolytic capacitor/rectifier 2006
This is an unusual experiment which is very simple and is detailed
here. Basically two
aluminium electrodes in a sodium bicarbonate solution will glow and sparkle
with sufficient applied voltage. One electrode is aluminium foil and the
other is an aluminium bar.

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Left photo shows a sparkling of both electrodes with 150 VAC
applied. The
right photo shows a diffuse glow seen with dark adapted eyes, which
starts at about 60 VAC associated with a little sparkling of the solid
electrode.

Here's my take on what is happening. If you insert an aluminium electrode in
a solution then it will form an oxide layer and when the metal is positive
will block current flow. This, as I understand, is the basis for
electrolytic capacitors and the reason they are polarized. Here we have two
aluminium electrodes which is the equivalent of back to back electrolytics
which are then non-polarized.
Initially there is a lot of current flow e.g. 10V 1A but this rapidly drops
as the oxide layer builds up. After a few minutes there is little flow even
at 100 VAC. Exceed this however and things start to happen fast. At
150 VAC the current rises to 5 A (750 W) and widespread sparking is
seen particularly at the electrolyte/air/electrode junction. I
interpret this as breakdown of the oxide layer with voltage. There is a
diffuse glow starting at about 60 VAC but the sparkling becomes more
prominent with increasing voltage.
Note that the alkali solution boils rapidly with the heat. Eye
protection is very important here.

Spooky
Cornstarch 2006
Inspired by a
recent video I decided to do
make my own cornstarch fun. (Corn flour in Australia).
Essentially cornstarch liquid is a fluid whose viscosity is rate dependent.
You can hit it hard with a spoon and it will strike it and bounce off, but
can be spooned slowly and drip from a spoon. A real anti splash fluid.
On a flat plate under vibration the vibration is probably more marked at
discontinuities and edges (like a wave breaks at the seashore). This leads
to bizarre effects with cornstarch which gets forced up into stalagmites,
loops and bizarre writhing spooky shapes like pools of writhing undead...

Anyway it is very easy to do. Get the wife/girlfriend/significant other to
make a reasonably thick cornflour/cornstarch mixture. (This is a common
cooking ingredient). Get a small loudspeaker (I used 4 inch, 4 ohm, 3.5 W)
and feed it with 50 Hz / 60 Hz. I guess the speaker can still be in its
enclosure. Don't get cornstarch over your home theatre speakers
though as this will upset the wife/girlfriend/significant other.

Use a 6 VAC transformer or winding with a dropping resistor of 8 - 10 ohm 5
watt, or
use a variac. Even use the other speaker of a stereo pair as a
dropping resistor. I needed about 2.0 VAC i.e. 0.5 W.
Place some plastic cling film (Gladwrap in Australia) loosely over the
speaker so that a spoonful or two of the cornstarch mix will sit closely
applied to the speaker cone.

I did try a frequency generator and different frequencies but 50 Hz seems
fine, particularly as it dries a little and the viscosity rises.

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Photos above show varying effects as the power is increased.

I tried this with a subwoofer and the results were a bit disappointing
initially.

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The left photo shows the 12 inch subwoofer driven with 40 W at 50 Hz
(12 VAC). The right photo shows only limited extension of
the corn flour. Removing the plastic had little effect until I got out the
frequency generator and a 100 W audio amp and picked out the resonant
frequency of about 22 Hz where cone excursion was greatest and up to one
inch.

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The left photo shows the 12 inch subwoofer driven with 40 W at 50 Hz
(12 VAC). The center photo shows a shot at 25Hz where the
corn flour lumps get thrown around. The right photo shows
a close-up of one of the airborne lumps.

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You can get some unusual shots with the funny properties of corn flour. Here
I was pouring it out with a spoon. The pour is falling but nowhere
near as fast as it should.

Zamboni battery (sort of) 2006
I have been keeping an eye out for suitable materials to make a Zamboni
battery for some time now.
A Zamboni battery or
Duluc dry pile
is a battery made of thin discs of metal (often copper-zinc) separated
by paper which is kept slightly conductive by the humidity. By stacking up
thousands of these a battery of thousands of volts at an extremely low
current can be made. This is enough to drive devices that run on charge such
as Franklin bells. The
Oxford Electric bell has been running since 1840.
I have used electrodes that are used for taking ECG's (electrocardiograms)
of which 10 are used for each recording and are single use then discarded.
The electrodes are silver coated plastic coated with a silver chloride
impregnated gel which is sticky. The silver is exposed on one corner to
allow the electrical connection to a crocodile clip.
So could these be used to make multiple cells?

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The left photo shows the electrode on my hand and the underside of
another one. I have also connected it to a meter to show that 0.6 V is
generated across this cell to my hand. The center photo shows
0.7 V when connected to some aluminum. Current at short circuit is 1mA.
The right photo shows the result with thin strips in series generating 2.9
V. Contact between the aluminum foil and the silvered electrode is
tenuous without pressure though.
So small batteries are possible with cheap materials. I am exploring
other configurations in an effort to keep things simple and reliable.
I need to think about the oxide layer forming on the aluminum as in the
electrolytic
capacitor above.

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Above shows one of my batteries a year later. The aluminum foil has
almost disappeared. There was little residual voltage but I could charge it
up sufficiently to dimly light a LED.

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Here is another battery made from small squares of zinc plate each of which
is tack soldered to copper foil squares each touching the electrolyte gel of
a pad. Initial short circuit current is about 20 mA but this falls
rapidly and this LED is being driven at 1.5 mA. Open circuit voltage
is 4.8V so about 0.84V per cell.

Water travels uphill
under its own steam
2006
This idea comes from a New Scientist article earlier this year. Essentially
a water drop will travel uphill on a very hot ratcheted surface on its
blanket of steam.

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The left photo shows a close up of a large drop of water dropped onto
a hot ratcheted surface. It is traveling uphill from left to right.
The surface was made from the iron laminations from a very small
transformer. They are held in place with a crocodile clip onto an
aluminium bar and are tilted downward from left to right. The spirit level
in the background is dead level as is the camera. The centre photo shows
two drops travelling uphill. The
right photo shows a drop that has gone up the hill and down the other
side.

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The left photo shows the MAPP gas blowtorch heating the laminations
to 287 degrees C. The centre photo shows the infrared thermometer.
Temperatures have an optimal range of perhaps 200 - 300 degrees C The
right photo shows that the temperature has dropped to around 140
degrees and a water drop will wet the iron and boil with splashing and
disintegration of the drop. Apparently the same happens with many
liquids including alcohol and liquid nitrogen.

Bernoulli Ball 2008
Here are two
Bernoulli balls stabilized by three peacock feathers.
Leaf blower power. Very much more stable even in a significant cross wind
which a normal Bernoulli ball will not tolerate.

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The story behind the peacock feathers: There is a dedicated Bernoulli setup
at the Gravity Discovery Centre in Western Australia where I have 4
displays. It will blow up two 6-8 inch plastic or polystyrene balls.
Peacock feathers are also sold there and one visiting child stuck several
into the polystyrene ball. While his father was berating him the Centre
attendant noted that it was really stable so they got left stuck in.
I picked up a few feathers to experiment myself.

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The addition of a smoke generator helps to show the airflow.

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The pic shows one of my new purchases - one of three stainless steel gazing
balls which had been floating in an ornamental pool for 3 years unsold in a
garden place.
It is being levitated only a few millimeters due to the weight but will
still rotate quite freely.
I didn't realize the appropriateness of my t-shirt slogan until I had
already set things up.

Photos above show a sparkler attached to an electric drill and a 5 second
exposure.

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Above left photo - Jaimie are you ready? Centre photo: Jaimie
unwittingly pushes the RED BUTTON and explodes. The
right photo shows how it was meant to be done. Same sparklers in a
cordless drill but using a rotating color filter.

LED light patterns
2008
A selection of photos of moving LED light sources shows them in a new light.

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Above left photo This is a small commercial battery powered LED array
that my wife wanted suspended above the BBQ. I have covered one of the
LED's with blue cellophane. The
right photo shows it suspended above the camera. Now just give the
lights a push and take a time exposure.

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Above left photo Pushing the array in a simple circular motion with
some spin gives intricate geometric patterns. Center photo It's like
you could almost grab it. This looks very much like a toroid used on
top of my Tesla coils. The
right photo shows the path followed by the one blue colored LED.

This next one below is a little fan with programmed LED's in one of the soft
plastic blades and was bought in Hong Kong (thanks Gail). The flash rate and
sequence of each LED varies.

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Above left photo The fans with its 5 LED's is stationary. The
right photo shows it running and you can see the pattern which
constantly changes.

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Left and centre photos show the fan rotating spiral giving a lot of
detailed patterns. Pushing the array in a simple circular motion with some
spin gives intricate geometric patterns. It's like you could almost
grab it. This looks very much like a toroid used on top of my Tesla
coils. The
right photo? Hmm.. only a mother could love a nerd like this.

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Left and centre photos show drawing with light using a handheld
LED torch and a fiber optic spray. The right photo shows me drawing
what looks a bit like a lightning bolt next to me.

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Above left photo shows my version of "plasma whip" modelled on the
IronMan 2 version. The
right photo shows the effect from two small decorative neon tubes spun in a
circle.

Strobe Light
effects2009

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You see some strange creatures attracted to the shed lights at night.

Mystery Photos
2006
A selection of photos that are not instantly recognizable for
what they are. The explanation and supporting photo follows down the
page:

Photo 1 below

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Photo 2 below

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A typical Australian road about 5 minutes from home. Something is not right
but you have to enlarge the photo and look carefully for the key. It changes
the whole interpretation.
.
.
.
.
.
.
.

Answers below:

Photo 1 An angle grinder cutting through a pipe with the view down the
pipe.

Photo 2 The shot is a 5 minute exposure on a cloudy and very dark
night. The key is the streaks of stars in some areas. This is
what it really looks like with car headlights on.